Amsterdam police called for the public to provide information on a possible child pornography ring Monday after a teacher was arrested on suspicion of molesting dozens of very young children.

The 27-year-old suspect worked as a substitute teacher for at least two preschools in the city and also offered baby-sitting services online in what is feared to be one of the worst cases of sexual abuse in the Netherlands, the city's mayor said at a late-night press conference Sunday. (AP)